The present invention relates to a vehicle and to a method for reducing loading of a vehicle occupant in the case of a crash.
In order to reduce a danger of injury for vehicle occupants in the case of a crash, vehicles can be designed in such a manner that the force introduction on the respective occupants takes place as long as possible on the one hand and that a certain maximum force is thereby not exceeded on the other hand. The problem is hereby that, in the case of a crash with a high vehicle speed, there is no time to slowly carry out the force increase at the occupant. At the same time, a fast force increase is disproportionately uncomfortable for the occupants with cases of a crash with a low vehicle speed. Vehicles are accordingly designed regularly with a compromise with an average vehicle speed in the case of a crash.
German patent document DE 103 57 015 A1 discloses a vehicle which has a force transfer element in an engine chamber. This can remove at least the engine mass early from the energy-absorbing force path (crush zone), whereby the time available for the force build-up at the occupant and for the deceleration of the vehicle can be prolonged.
In German patent document DE 197 38 620 C1 an electric vehicle has a traction battery that is arranged in a battery trough, and can be displaced in the longitudinal vehicle direction along at least one sliding tube. In the case of a crash, the large mass of the traction battery can thereby be braked over a longer path of deceleration, which reduces the danger of a damage of the traction battery.
Published U.S. Patent Application No. 2003/0184124 A1 discloses a vehicle whose front region is designed in such a manner that, in the case of a crash, a crush zone arranged in front of an engine is first crushed, and that, with further deformation, a support frame behind the engine bends and thereby enables an energy-absorbing rotation around a transverse axis of the vehicle.
One object of the present invention is to provide an improved embodiment for a vehicle or for a method of the above-mentioned type, which is especially distinguished by an improved occupant protection in the case of a crash.
This and other objects and advantages are achieved by the crash protection method and apparatus according to the present invention which is based on the general idea to accelerate a partial mass of the vehicle absolutely (that is, not only relative to the remaining vehicle) in one direction in particular in a direction which is opposed to an effective direction in which a force introduction into the vehicle is expected in the case of a crash. In other words, with a frontal crash during a forward drive of the vehicle, the force acting on the vehicle is opposed to the drive direction of the vehicle and effects as a result a deceleration of the vehicle. According to the invention, a partial mass of the vehicle is now accelerated opposed to this force, acting in an effective direction that is in the drive direction of the vehicle, and namely in an absolute manner.
The absolute acceleration of the partial mass means that the partial mass that has the same speed as the remaining vehicle at the start of the case of the crash, is additionally accelerated in the current movement direction of the vehicle in addition with regard to the environment. This absolute acceleration thus increases the kinetic energy of the partial mass. By the acceleration of the partial mass, a repercussion is however generated which is supported at the remaining vehicle, which consequently has the same direction as the force introduction into the vehicle which is expected in the case of a crash. The suggested acceleration of the partial mass thus leads to a force introduction into the vehicle which delays the vehicle. This effects a force introduction onto the vehicle occupants.
With the help of a corresponding crash detection device, it is possible to detect a crash (that is, a collision of the vehicle with an obstacle) at a time when the expected force introduction at the vehicle due to the crash is not yet (or not yet completely) built up. The vehicle can therefore be decelerated at an earlier time with the help of the acceleration of the partial mass, in order to prolong the time which is altogether available for decelerating the vehicle. The respective crash detection device can for example detect the imminent crash, even before the vehicle contacts the respective obstacle.
The deceleration of the vehicle caused by the acceleration of the partial mass additionally causes the vehicle occupants to be already sensed by corresponding restraint systems, as e.g., a safety belt, whereby in particular a so-called belt slack is removed from the restraint system. This measure makes the introduction of larger deceleration forces more bearable for the occupants.
A sensor can also be used as a crash detection device, which only detects the crash from the contact of the vehicle with a collision object, e.g., an acceleration sensor. The acceleration of the partial mass is then naturally only possible from the crash detection.
The invention is in principle based on the consideration that the deceleration characteristic in the case of a crash can be influenced by the use of the repercussion during the acceleration of the respective partial mass. This is in principle possible for all six degrees of freedom of the vehicle, that are the translations in the three directions and the rotation around the three axes.
For realizing this principle, the vehicle is equipped with an acceleration device, which cooperates with a corresponding crash detection device. The acceleration device can accelerate absolutely in dependence on the respective case of the crash, namely against the effective direction of the force introduction, which is expected in the respective case of a crash. In particular, the engine of the vehicle constitutes a partial mass suitable for such acceleration. A fuel tank or, for example with an electric vehicle, a traction battery are also suitable. A displaceable mass in a longitudinal beam is however also conceivable, wherein a smaller mass by means of acceleration, also a larger end speed with a longer path can also be compensated.
Corresponding to an advantageous embodiment, a holding device cooperating with the crash detection device can be provided, with the help of which the respective partial mass can be fixed to the remaining vehicle during a normal vehicle operation, and which can release the respective partial mass relative to the remaining vehicle in the case of a crash. The engine can for example be fixed in a rear vehicle position with the help of the holding device, so that it can be accelerated to the front in the case of a crash.
Further important characteristics and advantages of the invention result from the dependent claims, the drawings and from the associated description of the figures by means of the drawings.
It is apparent that the above-mentioned characteristics, which still will be explained in the following, can be used not only in the respectively given combination but also in other combinations or on their own without leaving the scope of the present invention.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.